diff --git a/CHANGELOG.md b/CHANGELOG.md
index 027ae7cf..9a68b174 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Add unit test for js/class.js.
 - Add unit tests for function `roundValue` in currentweather module.
 - Add test e2e showWeek feature in spanish language.
+- Add warning Log when is used old authentication method in the calendar module.
 
 ### Updated
 - Changed 'default.js' - listen on all attached interfaces by default.
diff --git a/modules/default/calendar/calendar.js b/modules/default/calendar/calendar.js
index ad71ea75..ad3be8ce 100644
--- a/modules/default/calendar/calendar.js
+++ b/modules/default/calendar/calendar.js
@@ -79,7 +79,9 @@ Module.register("calendar", {
 			};
 
 			// we check user and password here for backwards compatibility with old configs
-			if(calendar.user && calendar.pass){
+			if(calendar.user && calendar.pass) {
+				Log.warn("Deprecation warning: Please update your calendar authentication configuration.");
+				Log.warn("https://github.com/MichMich/MagicMirror/tree/v2.1.2/modules/default/calendar#calendar-authentication-options");
 				calendar.auth = {
 					user: calendar.user,
 					pass: calendar.pass